A METHOD FOR REDUCING VOLATILES IN POLYETHYLENE PELLETS

摘要

A method for reducing volatiles in polyethylene pellets that comprises the steps of: a) retrieving the pellets from the extruder (1) and pushing them through a cooling pipe (3) with a stream of cooling water and with a residence time sufficient to reach the desired temperature; b) separating the pellets from the water in a dryer (4), returning the water to the cooling system via a cooling device (5) and pushing the cooled pellets through a pipe (9) into the heating silo (10); c) keeping the pellets for a period of time of from 5 to 50 hours in the heating silo under a stream of hot gas (11 ) entering near the lower end of the heating silo and escaping through the upper open surface; d) continuously retrieving pellets through the bottom part of the heating silo via a valve (24) that allows control of the exiting flow of material in order to keep the heating silo constantly full; e) feeding the pellets to the cooling device (25); f) keeping the cooling device at room temperature to bring the pellets' temperature down to the desired level of from 60 to 70°C; g) sending the cooled pellets to the homogenisation silos.